One type of railroad freight car in use today is an open-top hopper car wherein an elongated walled enclosure or hopper holds material there within. The hopper is mounted on a mobile frame or undercarriage and defines a longitudinal axis for the car. Such railcars are used to transport aggregate, iron ore, coal and other materials and offer an advantageous economical method of transporting large amounts of materials between distant locations.
The granular commodities or materials can be rapidly discharged from the hopper through a discharge opening defined by the hopper. In many open-top railroad hopper cars, one or more doors are pivotally mounted or hinged along an upper edge to the hopper for vertical swinging movement between closed and open positions relative to the discharge opening. When closed, the doors prevent discharge of materials from the hopper. When released from their closed position, the doors gravitationally swing toward an open position assisted by the material moving through the discharge opening.
As will be appreciated, different door operating devices have been proposed to releasably maintain the doors in their closed position. It is important to note, however, such door operating devices are specifically designed to the particular application with which they will find use. For example, a device used to operate longitudinally mounted swinging doors on a railroad hopper car cannot, without substantial modifications and redesign, be used to operate transversely mounted doors on a railroad hopper car. Conversely, and primarily because of the disposition of the doors on the railroad hopper car, known devices used to operate transversely mounted swinging doors on a railroad hopper car cannot, without substantial modifications and redesign, be used to operate longitudinally mounted swinging doors on a railroad hopper car.
Designing an apparatus used to control operation of the doors of an open-top railroad hopper car used to transport ore, coal and like materials, is complicated by the relatively heavy weight of the materials. That is, the weight of the materials carried in the railcar hopper impart a significant columnar load to the doors in the closed position. Moreover, and once the doors are released from their closed position, the gravitationally falling material tends to force the doors open with significant force. As such, the mechanism used to control operation of the doors must have sufficient strength and rigidity to perform under conditions wherein significant loads and forces are imparted thereto during all phases of door operation.
Once a hopper car reaches an unloading site, the doors on the hopper are swung open and gravity normally causes the material within the hopper to flow therefrom. As mentioned, however, the materials within the hopper exert a relatively large columnar load on the doors. Such downward load on the door has caused and continues to cause a significant problem in manual opening of the doors at the unloading site. Of course, at the unloading site time is of the essence and any complications involving opening of the doors to unload the material from the hopper prevents serious concerns.
In some applications, mechanized openers are used to operate the railroad hopper car doors. These mechanically driven openers include a rotatably driven member which must be aligned with and engage a free end of an operating shaft forming part of the door operating mechanism. As such, and unless the opener is timely removed from engagement with the operating shaft of the door operating mechanism, and as the doors swing to their open position, the significant loads acting on the doors by the gravitationally falling materials moving through the discharge opening can be transferred to the driven member of the opener. Besides the problems involved with properly aligning the driven member of the opener to the operating shaft of the door operating mechanism, these transferred loads can and often do result in significant damage to the opener. Moreover, and as the railcar moves along the rails during the unloading process, the mechanically driven opener is dragged along therewith, thus, imparting other loads and forces to the apparatus used to control operation of the doors.
Because some railcar hoppers are of an open-top design, the material in the hopper car is continually exposed to the environment and weather conditions. In cold weather environments, the particulate material in the open-top hopper frequently freezes together thus hindering their discharge from the railcar hopper. Such conditions often require workers at the discharge sites to strike the sides of the railcar hopper with large hammers in an effort to loosen the frozen materials and create a flow of material through the discharge opening. As will be appreciated, and besides the adverse time consuming affects resulting from such needed manual efforts, striking the hopper with a large hammer can also result in significant damage to the railcar.
Thus, there is a need and continuing desire for an apparatus for controlling the positive discharge of materials from a railroad car having an open-top hopper notwithstanding the environment while facilitating use of and offering protection to a driven opener used to open the doors of a railroad hopper car.